LYMPHATICS IN TAIL REGION, SCORP.ENICHTHYS 29 



nection with the caudal vein it must be said to take its origin 

 above the last vertebra from the anastomosis of the two profundus 

 portions of the lateral trunks (figs. 3-7, L.T.(2)) and the posterior 

 neural trunks (figs. 4, 6, and 7, P.Neu.T.). As stated previously 

 the latter vessels collect a network from the sides of the last inter- 

 spinal bones; while the profundus portions of the lateral trunks 

 would in all probability collect most of the lymph from the pos- 

 terior portions of the lateral trunks (figs. 4, L.T. (d) and some from 

 the main lateral trunks (fig. 4, L.T .), but as the latter trunk in- 

 creases in caliber caudo-cephalad the resistance must be less 

 in that direction, with the result that most of the lymph flows in 

 that direction. In Clinocottus the posterior portions of the lat- 

 eral trunks are also in communication with the posterior caudal 

 sinus, in which case the lymph received by that sinus could find its 

 way into the posterior portions of the lateral trunk and thence 

 into the longitudinal neural trunk, or the lymph from the posterior 

 portions of the lateral trunks could go in the opposite direction, 

 namely, into the posterior caudal sinus, in which case it would 

 ultimately find its way into the longitudinal neural or haemal 

 lymphatic trunks through the dorsal or ventral caudal fin lym- 

 phatic trunks. On one side of the tail in Scorpsenichthys the 

 caudal lymphatic trunk communicates with a profundus portion 

 of one of the lateral trunks, hence a possible supply from that 

 source. A most important accession, however, is the next to the 

 last neutral trunk or the dorsal caudal fin trunk (fig. 4, Neu.T. (d) 

 which joins the longitudinal neural trunk opposite the third ver- 

 tebra from the last. It is an enormous trunk formed by the anas- 

 tomosis of the small dorsal trunk (fig. 4, D.T.) and the large dorsal 

 caudal fin trunk (fig. 7, C.T. (d). As previously stated the latter 

 trunk collected the lymph from the upper half of the caudal fin 

 and doubtless some from the posterior caudal sinus. In other 

 words then, a glance at fig. 4 shows the arrangement of the lym- 

 phatics to be such, that it would be possible for the lymph from 

 the entire tail region to reach the longitudinal neural trunk, but 

 under ordinary circumstances, however, it is probable that a large 

 portion of the lymph reaches the longitudinal haemal trunk through 

 the ventral caudal fin trunk. The flow of h^mph in the longi- 



